[Avodah] measurement error

[Micha Berger via Avodah]

On Sun, Jan 11, 2015 at 01:52:11PM -0500, Micha Berger wrote:
: In an appreciated bit of siyata dishmaya, my Arukh haShulchan yomi
: sechedule <http://www.aishdas.org/luaach> brought me to a primary source
: on this subject -- AhS OC 363:32-35. The he.WikiSource.org ("Vikiteqst")
: copy is at <http://j.mp/1DMRNlm>
...
: When dealing with mavui, where there is only one mavui and therefore one
: measuring process to be used for everyone, the above applies. However,
: when the measurement is only for one person's use, tbey should be
: measuring for himself, with his own norms.

: And here he adds a touch of subjectivity: a person should measure how
: far he himself could walk. And the rule of carrying in rh"r a distance
: of no more 4 of one's own amos is brought into that umbrella.

: The reason for the general rule is to cover the personal amos of the
: people who will be using the measuring.

: BUT, and this is why I do not follow, he opened se'if 32 by telling us
: the variability is 1/48 of the total (1/24 of an etzba per ammah). Which
: is far less than the variability in forearm lengths in most groups of
: people. For example, my own sukkah is used by Yoni, who stands 6'3" and by
: my own 5'3" -- and my arms are on the shorter side, even proportionally.
: When we hold up elbows together, my ammah ends just past his wrist. Not
: within 47/48 of eachother.

I came across another AhS datapoint for this thread, OC 586:14.

He quotes the Rambam Shofar 1:5, discussing the minimum length of a
shofar: that you can hold it in your hand and it's visible on either end.

The AhS explains the intent as being the size of the toqei'ah's hand, but
rather an average person's hands, "veshi'uro tefach sheheim 4 godelim".

Then there is a debate whether the tefach has to be a generous one, so
as to be visible (Tur, quoting Ri Gei'os) or a narrow one (Tur himself
and SA), which is still visible if the toqei'ah uses four fingers --
after all, they'll still be narrower than 4 thumbs.

So the shiur is neither personal nor really the standard tefach. It is
literally as the gemara says, what can be held and still seen. Which is
why there is a machloqes about where the tefach stands in relation to the
real shiur. But, visible if hypothetically held by an average hand. And
if the tqoei'ah has wide hands, he could hold a minimal shofar without
it being visible, and it would still be kosher.

The AhS also says this was already explained in Nidah 26b, which is a
depressing gemara about miscarriages, and a tefach comes up in shiurim
for tum'ah, but I didn't see where it mentionrs our topic of what kind
of tefach is used.

What I find even more interesting is that there is no chiluq being drawn
between someone who blows in shul and someone who blows just for himself.
Wouldn't the rule from OC 363 mean that someone in the latter situation
should use what is visible when their own hand holds it?

Tir'u baTov!
-Micha

-- 
Micha Berger             Today is the 44th day, which is
micha at aishdas.org        6 weeks and 2 days in/toward the omer.
http://www.aishdas.org   Gevurah sheb'Malchus: What type of justice
Fax: (270) 514-1507                            does unity demand?